One-piece undergarment



FIG. 1 is a front elevation view of a one-piece undergarment showing my new design;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a right elevation view thereof;

FIG. 4 is a left elevation view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken line shown in the drawings is stitching and forms a part of the claimed design. 

The ornamental design for a one-piece undergarment, as shown and described. 